This invention relates generally to video cassette recorders (VCR's) for television systems and specifically to VCR's for television systems wherein multichannel signals are receivable, including an encoded channel signal viewable only with an appropriate decoder device.
In addition to over-the-air, "free" television broadcasts, a large demand and corresponding market for cable-connected "pay" television and over-the-air, "pay" television broadcasts has arisen. Cable systems involve a direct connection or cable to each subscriber's television receiver. The cable operator supplies to his subscribers all normally receivable over-the-air television signals in the area as well as special programming and in many instances, locally originated programming. The cable may also carry one or more encoded signals which can only be received by subscribers who have paid an additional fee for an appropriate decoder mechanism.
There are also over-the-air "pay" television signals that, while being receivable by all conventional television receivers, are only "viewable" by television receivers operated in conjunction with suitable decoders. In this arrangement the broadcast television signal is scrambled so that a decoder-less television receiver will not produce a viewable picture and/or acceptable sound.
In general, television receivers connected to cable systems are not used for over-the-air signal reception and receivers arranged to receive broadcast signals are not used for cable reception.
VCR's, which are simply tape recorders for television signals, have also grown in popularity and afford the viewer a great deal of flexibility in his viewing habits since television programs may be recorded for viewing at a later time. It is common to find television receiver installations having a cable system (or an over-the-air system) with an encoded channel capability operated alongside a VCR. Indeed, both the television receiver and the VCR may be equipped with remote control devices for complete operation from the viewer's easy chair. Thus has arisen a need to permit the viewer complete flexibility in determining whether to record a particular channel including a pay or encoded channel while watching another channel or record the channel he is watching--all from the comfort of his chair.
VCR's are presently capable of permitting the viewing of any received television channel signal while recording any other television channel signal, including the received one except where a channel signal requires a decoder. Thus, without the use of external splitters and RF switches, it is not practical to watch one channel while recording another if either of the channels involved requires a decoder, i.e., is a pay channel.
There have been recently proposed VCR arrangements which in one instance would enable simultaneous recording of a pay channel while viewing another channel or vice versa, but which would entail added signal loss by requiring another signal splitter in addition to the signal splitter normally included in the VCR. Consequently, there is a need in the art for a VCR which is capable of permitting viewing of any channel while recording any channel, including channels requiring separate decoders, without incurring additional signal loss or complicated external switching schemes.